First, take your frozen mash ...

Accompanied by accusations of hypocrisy, betrayal and cynicism, Delia Smith's latest bestseller, How to Cheat at Cooking, has caused quite a stir. But can tinned mince, frozen aubergine and canned onions ever be a good idea? Jon Henley invites sceptical but curious chef Aldo Zilli to rustle up five of Delia's new dishes, while our panel of six food experts addresses the all-important question: what do they taste like?

Eight-thirty in the morning is not, frankly, the kind of hour at which any civilised person would generally wish to find themselves in a smart Soho restaurant. But the mood in this place, part of the small but growing empire of eateries owned by the irrepressible Italian chef Aldo Zilli, is surprisingly cheerful. It's not as if we're exactly looking forward to what is about to be set before us, I'd say. But we are undeniably intrigued.

Gathered round a long table by the window are Samantha Greer, a delightful school cook from New North Community School in Islington, north London, where she prepares 2,000 meals a week; William Sitwell, the elegant and informed editor of Waitrose Food Illustrated; Giles Coren, reliably caustic columnist, restaurant critic and TV personality; Sybil Kapoor, formerly a chef and now an admired food writer; the ebullient and altogether larger-than-life Charita Jones, aka Momma Cherri of Momma Cherri's Soul Food Shack in Brighton (slogan: "You might come in skinny, but you ain't goin' out that way!"); and James Nathan, a charming and admirably diffident young man who has just won Masterchef.

In the kitchen, maestro Zilli and the chef at his restaurant Zilli Fish, Pasquale Amico, are swearing over a new and controversial recipe book. Actually, only Aldo is swearing. Pasquale is just getting on with it, albeit bearing a look of slightly pained incomprehension.

We are here because we are going to cook (in Aldo and Pasquale's case) and consume (in everyone else's) five dishes from Delia Smith's hugely successful new tome, How to Cheat at Cooking. Besides leaping to the top of the bestseller charts before it was even published, Delia's first book in five years has already resulted in nationwide shortages of frozen mashed potato, anchovy fillets, dried porcini mushrooms, pine nuts, tortellini pasta, Roquefort cheese, ready-made pancakes, tinned minced lamb, boiled and peeled eggs and pre-cooked fish at Sainsbury's, Tesco and Asda. And the TV series tie-in on BBC2 drew 4.1m viewers on Monday.

There's no getting over it: How to Cheat at Cooking has caused a bit of a fuss. The problem is that the point of the book, and the series, is that cooking can be made quicker and easier by using selected processed ingredients. That "cheating" at cooking, and using ready-sliced this and frozen that, is not just OK but good. As Delia has said, the book is aimed at helping people who feel they are too busy to cook, or too scared, to create healthy, tasty meals. "I think I will have performed a great service if I can make it possible for families to sit round and eat a meal together," she has said. "That's my mission."

Some say this means Delia, the woman who taught the nation to cook, has simply sold out, and we will return to that later. But what, first, does new-style Delia actually taste like? After all, back in 1998, in the foreword to the seminal How to Cook, Book One, she wrote that it was her "personal belief that we may be in danger of losing something very precious, and that is a reverence for natural ingredients and the joy and pleasure they can bring to real life ... The sensual pleasure of eating belongs to everyday life as well, and it's not always to be found in the vast amounts of mass-produced, easy-cook fast foods that we're subtly persuaded to eat ..." How, then, do chocolate cupcakes made with Aunt Bessie's homestyle frozen mashed potato fare on the discerning palate? How much "sensual pleasure" is to be found in moussaka made with tinned minced lamb and frozen chargrilled aubergine slices? Or, indeed, in Wild Mushroom Risotto made with, um, two sachets of Asda's frozen mushroom risotto, dried porcini and a slug of madeira wine? That, dear reader, is what we are here to find out.

In Zilli's kitchen, Aldo is cooking up a storm. The Chicken and Leek Pot Pies are already in the oven, the Chocolate Cupcakes are done and the Amazing Moussaka is in full swing. "I have to admit," he remarks dubiously, "that I haven't actually used tinned meat since I was a kid. Italian spam, it was. I hope this is better than that. And frozen aubergines - not in themselves a bad product, but they need a lot of flavouring. And I doubt they've been sweated off, so there'll be a lot of bitter water coming off when we cook those. I've got a lot of time for Delia, honest I have. But I do get the feeling in this book that at times she's gone a bit far, you know? Cooking is cooking, after all, isn't it?"

Of the Wild Mushroom Risotto, the chef sniffs that it is "actually quite a lot harder than making a normal risotto. I'm sorry, Delia, but a real risotto takes 25 minutes from scratch. This is 40 minutes because of the dried porcini, and the rest is pre-cooked. So I can't really see an awful lot of point in that. And the madeira's a strange choice; I'd use a more neutral white." Rustling up the omelette, Aldo is profoundly shaken by the sight of the ready-crisped bacon. "What the hell's that about, then?" he demands. "It takes 30 seconds to crisp up thinly sliced bacon. This is dire; they'll never touch this if I show them the packet. For this one, cooking fresh would be quicker and easier. Cheaper too, I reckon."

Delia, opines the chef, adding a generous fistful of parmesan to the risotto, "taught this country to cook, no doubt about it. All that early stuff, how to boil an egg, we laughed but it was necessary. It still is, actually: we're running away too fast with this cooking lark, a lot of kids don't know the difference between courgettes and aubergines, or onions and fennel. And it all starts at home. There's still a huge need to learn, and there's definitely room for a few more like Delia - or like Delia was - to teach them. I'm not sure about this cheating business, though. Not sure at all."

It is time, though, to taste. Out, first, comes the steaming risotto. "This," remarks Giles kindly, "is like having a pig piss in your throat. It tastes of freezer and plastic. I don't understand. If you can't cook and you can't afford to go out, eat a cheese sandwich." William, and most of the others, are rather kinder: "Perfectly passable," he ventures. "It could be a little better seasoned, but I've eaten far worse." The chicken and leek pies fare less well. "This is inedible," says Sybil. "Like school dinners," says William. "Excuse me," says Samantha, the dinner lady. "I resent that." Giles wonders innocently whether Delia couldn't have specified a rather more expensive cut of rat.

The Amazing Moussaka, regrettably, attracts an almost unanimous chorus of revulsion. "This," says William, "is supremely awful. Terrible beyond belief. It's a crime against aubergines. They're such beautiful vegetables, and to see them treated like this. It's appalling." Giles, for his part, refuses point blank to put it anywhere near his lips. "Why would you eat tinned mince?" he asks, deliriously. "It's like a lamb shat in a tin." William wonders about the logic of using tinned meat, but fresh mint. Sybil reckons that if you were reduced to this, you'd be better off buying a whole ready-cooked meal. Even James looks mildly nauseous.

But the omelette - hurrah! - fares really quite well, apart, of course, from the tinned onions, which taste of nothing and of which there are far too many. And the cupcakes pretty much disappear, even if only William actually seems to be eating them. At the end, Aldo's proffered cappuccinos are gratefully, nay frantically, accepted. "I've never had so many bad comments about my food in my life," he cracks. "Fay Maschler, eat your heart out," he says, referring to the London Evening Standard's notoriously exacting restaurant critic. Everyone laughs, but just a bit too loudly. Thank God, the laugh seems to say, that's over.

But what, once it was all over, does our panel think Delia is up to? She hasn't made our shopping any easier, that's for sure. Or cheaper. In the first flush of the nation's latest bout of Delia-mania, finding her chosen ingredients proved something of an ordeal. After scouring the local supermarkets for the ingredients for this morning's little dégustation, we had to get the McCain potato rostis for the Shortcut Omelette Savoyard couriered - couriered! - from McCain in Scarborough. (There is a shortage of McCain potato rostis in the south of England. You will be lucky to find any there in the next three weeks.) And the Eazy fried onions were biked from the nearest stockists, in Leatherhead, in Surrey. A tenacious colleague tracked down the frozen mushroom risotto to a distant Asda on the Isle of Dogs, while the pink chocolate buttons for the Chocolate Cupcakes turned out to be available only from the Jane Asher shop in London SW3 - Chelsea. So we bought Cadbury's white ones instead.

But others have argued, with equal passion, that such reactions are merely middle-class food snobbery at its worst. "I'm unlikely ever to make a recipe in that programme," wrote one poster, "but I know a lot of people who are: the ones most likely living on ready meals at the moment. A lot of people don't cook at all, and they are the ones this is aimed at. Like it or not, stuff like this will get people back into their kitchens." The Delia-detractors, agreed another, are spouting "ridiculous, offensive nonsense - supercilious rubbish".

Our illustrious panel is divided. "She's after the money," says Giles, charitably. "I think she's jealous of Jamie and Nigella and Hugh. It's like old footballers who bemoan the fact there was never any money in the game when they were playing: Delia was a food star when food stars weren't big. It's like some old boxer coming out of retirement, Rocky Seven up for one last slugging match. But what she doesn't realise is that the rules have changed, that nowadays people are motivated by different things: the environment, quality ingredients, nutrition. She's come back for her slice of the pie - that's her motivation."

William is kinder. "I really salute her for the idea of bringing an end to food snobbery," he says. "The message that it's OK to cut corners. The problem is, and this is what depresses me, that when you put it into practice, she's actually cutting off her nose to spite her face - I reckon shopping is actually harder with things like this, and the cooking is actually more complicated than it need be. It's like she's tried to cut corners, but in the process she's created this twisting chicane only to bulldoze her way through it. I actually think the road is straighter and less rocky than she makes out."

Samantha, for her part, really doesn't get it. "She's not saving time, and she's not saving the environment," she concludes. "I don't know what she's trying to do, actually. It's weird. She was trying to wean us off convenience foods, promote healthy eating, now she's asking us to use them. What's that about? And I'm not sure where you'd get half these ingredients. I've never actually seen tinned lamb's mince. If someone really, really doesn't want to cook, I'm sure they'd be better off with a ready meal."

What worries Sybil is that the ingredients for many of Delia's new dishes are "unhealthy, processed, environmentally unfriendly, high in fat, high in salt ... But worse, the recipes involve cooking skills without delivering a good product at the end. To get people to cook, it has to be a joy and a pleasure. I have no objection to semi-processed food, but the level of processing here ... I just don't get it. Delia is so good at doing simple, healthy food that's a real physical pleasure to prepare and a joy to eat ... "

Charita Jones reckons the whole thing "will backfire. I can see what she's getting at, but where she's failed is that she's picked obscure products that you're really going to spend time having to go hunt for. Plus, they have to cost more. I'm disappointed. She taught the country how to cook, now she's teaching it how to get by without cooking. Why couldn't she just have said: 'If you don't have or can't get fresh mince, then use a tin.' People would have understood that. But to demand tinned mince from the start is just strange."

James, modest as ever, begs determinedly to differ. "My one real comment on all this," he says, "is that not everyone lives in London, not everyone can drop into their local deli to buy fresh ingredients on their way home from work. I've stayed with friends in the provinces, they both work, they both have two-hour commutes, they have two kids, they have to shop at big supermarkets and they have to buy for a month or so at a time. My point is, if you're getting people like that to do interesting things with frozen and tinned food that they'd be using anyway, where, really, is the harm?

· Aldo Zilli's autobiography, Being Zilli, is out now, published by John Blake, £17.99.

Samantha These weren't bad. They were good and crispy on the outside, nice and soft on the inside. Certainly passable.

Appearance 5 stars Taste 4 stars

William These were really disturbing. I didn't actually like them, but there was something in them that made me want to keep eating them. Then you hear there's frozen mashed potato in them, which is an extraordinary way to add starch to a dish. But still I couldn't stop eating them. Worrying.

Appearance 2 stars Taste 3 stars

Giles These were beyond horrible. They had the sheen of a freshly laid dog turd - and the consistency, with that potato in them ... Ugh. No resistance, no bite, nothing. Just an injection of sugar. It's not hard to make a fairy cake, for Christ's sake. Five-year-olds do it with their mums. Dismal.

Appearance 0 stars Taste 0 stars

Sybil I didn't really like the cakes: they had a very funny, cornflour-like taste. The chocolate buttons were good, though.

Appearance 3 stars Taste 2 stars

Charita I liked these. A lot of people didn't, I know, but for me it's not surprising to put potato in a dessert - I use a lot of sweet potatoes. The concept was quite clever, but if you're going to use a potato, why not boil it and mash it? It doesn't take long. And why use Green & Black's, the most expensive chocolate you can buy? Cocoa powder would have been more in keeping.

Appearance 5 stars Taste 5 stars

James I quite liked the taste, but it's a very funny concept. I'm not sure why you need flour and potato. A bit weird, that one.

Appearance 4 stars Taste 4 stars

Chicken and leek pot pie

412g tin M&S chunky chicken in white sauce £3.98

1 medium leek £0.44

1 small carrot £0.08

2 tbsp dry vermouth £7.09 (bottle)

1 tbsp half-fat creme fraiche £0.79 (tub)

1 tsp chopped fresh tarragon £0.69 (packet)

2 Jus-Rol frozen small individual puff pastry rounds £1.99 (packet)

1 egg £0.21

Total ingredients: £15.27

The verdict Scores out of five

Samantha Greer There was a lot of cream in this and a lot of vegetables, but not very much chicken. Plus, the chicken was terrible: soft, mushy, no taste whatsoever. Not a success, really.

Appearance 3 stars Taste 3 stars

William Sitwell This looked fairly decent but was totally let down by the chicken, which was dreadful - bland, no texture, stringy, horrible. The pastry and the veg were fine. Disappointing.

Appearance 2 stars Taste 2 stars

Giles Coren As unpleasant a piece of chicken as I have ever seen or eaten. Soft, squidgy, quite revolting. The rest was all right, but you could have bought two chicken thighs for less and made a far nicer dish.

Appearance 1 star Taste 0 stars

Sybil Kapoor Utterly horrible. It reminded me of the worst kind of school dinners. The pastry was tasteless and undercooked, it had that awful tinned-meat flavour, and the vegetables were almost raw.

Appearance 0 stars Taste 0 stars

Charita Jones This looked nice, but tasted foul. I didn't like the sauce at all. And I don't see the point of the tinned chicken - what's wrong with a couple of thighs?

Appearance 4 stars Taste 2 stars

James Nathan Looked nice, tasted fine. The veg were good and fresh. It's not haute cuisine, but that's not the point and if I had come home from a hard day's work I'd be happy with this.

Samantha Not at all bad, actually. There were too many onions, and they were really soft, watery and bland. But overall it wasn't a disaster. Probably the best of the bunch.

Appearance 4 stars Taste 4 stars

William Really tasty. The bacon was delicious and this was a warm, hearty dish. With a bit of salad and a slice of good crusty bread and a glass of wine, I'd be happy with this.

Appearance 4 stars Taste 4 stars

Giles This was all right. I didn't even mind the tinned onion. It wasn't what I'd call a nice omelette, but it was OK.

Appearance 2 stars Taste 2 stars

Sybil Initially, this was reasonable, but the aftertaste with the onions was really rather unpleasant. Edible, but disappointing. It would probably have been OK if it had been made with an ordinary onion.

Appearance 3 stars Taste 2 stars

Charita It looked good and tasted good, though there were too many onions and they didn't taste right. A real onion, browned up nicely, would have been fine.

Appearance 5 stars Taste 4 stars

James There was nothing wrong with this - but why the tinned onions? A fresh onion, caramelised, would have made all the difference, and it's not hard to do.

Appearance 5 stars Taste 4 stars

Amazing moussaka

400g tin M&S minced lamb £1.99

250g ricotta cheese £0.79

1 tub cheese pasta sauce £1.29

2 tbsp red wine £1.99 (half bottle Côtes du Rhône)

2 tbsp sun-dried tomato paste £1.59 (jar)

1 tsp ground cinnamon £1.31 (jar)

1 tbsp chopped fresh mint £0.69 (packet fresh mint)

2 eggs £0.42

Whole nutmeg for grating £1.54

(unable to find, 1 jar Schwartz ground nutmeg)

4 Asda frozen aubergine slices £2.20 (packet)

1 tbsp parmesan £2.80 (packet)

Total ingredients: £16.61

The verdict

Samantha Really horrible. I didn't like this one at all. The top had curdled, the mince didn't taste like mince, everything was wrong. Yuck.

Appearance 3 stars Taste 1 star

William This looked very appetising - bubbling and glistening on top, just the way it should be. Then you stuck your fork in and it let off this dreadful, congealed, awful odour. This dish is a crime against aubergines - they're a wonderful vegetable and to do this to them is really, really depressing. And the tinned lamb was frankly disgusting. Terrible.

Appearance 0 stars Taste -5 stars

Giles I didn't put this anywhere near my mouth. It looked and smelled so awful and everyone around me was in paroxysms of revulsion - I'm afraid I'm too smart to eat something that gets that kind of reaction. Moussaka's bad at the best of times, but this smelled like a crow had got trapped in the chimney and you couldn't find it.

Appearance 0 Taste n/a

Sybil This looked quite promising on first appearance, but it had the unpleasant aftertaste of tinned food. The aubergines were mushy and watery and the sauce had separated. Pretty horrible; like airline food.

Appearance 1 stars Taste 0 stars

Charita Shockingly horrible, unfortunately. You've got to know what you're doing with moussaka anyway, and to start from a basis of tinned meat ... Just awful. The worst of the lot, by some way.

Appearance 1 star Taste 0 star

James This looked good but, in fact, it was really pretty dreadful. Everything about it was wrong.

Appearance 3 stars Taste 2 stars

Wild mushroom risotto

400g Asda frozen mushroom risotto £2.88

(return taxi fare from Farringdon to Asda

Isle of Dogs £62)

5 g gourmet porcini mushrooms £1.97 (packet)

40g butter £0.99 (block)

1 clove garlic £0.35 (whole garlic)

110g chestnut mushrooms £0.89

75ml madeira £4.99 (bottle)

Fresh parmesan £2.80 (packet)

Total ingredients: £14.87

The verdict

Samantha Very cheesy, not much rice compared with the rest of the ingredients and a really, really bad aftertaste. This isn't one for me or my schoolkids.

Appearance 4 stars Taste 3 stars

William Very reasonable, quite a tasty risotto in fact. Personally, I'd have seasoned it a bit better, but the texture was nice and it was very tasty. It would make a perfectly nice, decent little supper - although I'd make it from scratch.

Appearance 4 stars Taste 4 stars

Giles This had the colour, smell and flavour of complete sadness. The first mouthful of mushrooms was kind of OK, but then you actually swallowed it and the aftertaste kicked in. Grim.

Appearance 0 stars Taste 0 stars

Sybil I thought the flavour was reasonable, but the texture . . . If it had been cooked for any longer it would have been like wallpaper glue. There wasn't much rice and it was very soft because it had already been cooked.

Appearance 3 stars Taste 2 stars

Charita Surprisingly edible. I'm not really a risotto or a rice person, but this was quite nice.

Appearance 4 stars Taste 4 stars

James I didn't have a problem with this. It had a nice flavour, though I wasn't sure the alcohol was properly cooked off. For me, this is pretty much how a risotto tastes.